Ultra-thin embedded semiconductor device package and method of manufacturing thereof

ABSTRACT

A package structure includes a first dielectric layer, semiconductor device(s) attached to the first dielectric layer, and an embedding material applied to the first dielectric layer so as to embed the semiconductor device therein, the embedding material comprising one or more additional dielectric layers. Vias are formed through the first dielectric layer to the at least one semiconductor device, with metal interconnects formed in the vias to form electrical interconnections to the semiconductor device. Input/output (I/O) connections are located on one end of the package structure on one or more outward facing surfaces thereof to provide a second level connection to an external circuit. The package structure interfits with a connector on the external circuit to mount the package perpendicular to the external circuit, with the I/O connections being electrically connected to the connector to form the second level connection to the external circuit.

CROSS-REFERENCE TO RELATED APPLICATION

The present application is a continuation of, and claims priority to,U.S. patent application Ser. No. 14/195,930, filed Mar. 4, 2014, thedisclosure of which is incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

Embodiments of the invention relate generally to structures and methodsfor packaging semiconductor devices and, more particularly, to anultra-thin power device packaging structure having power overlay (POL)interconnects that form all electrical and thermal interconnections inthe structure, with the packaging structure having reduced inductance.

Power semiconductor devices are semiconductor devices used as switchesor rectifiers in power electronic circuits, such as switched mode powersupplies, for example. In use, power semiconductor devices are typicallysurface mounted to an external circuit by way of a packaging structure,with the packaging structure providing an electrical connection to theexternal circuit and also providing a way to remove the heat generatedby the devices and protect the devices from the external environment.Alternatively, especially for higher power ranges, the power modulespackaging structures may have large terminals for connection to theexternal circuit which add significant inductance and increase the sizeof the module.

Most existing power device packaging structures use wirebonds, amulti-layer substrate (e.g., a direct bond copper (DBC) substrate), andare leaded (leadframe, etc.) or provided with bolted terminals forproviding electrical and thermal connectivity to the packagingstructure. The wirebonds make the connections from one surface of thepackaging structure to package pins, which then interface to theexternal circuit, with a DBC being connected to the other surface of thepackaging structure (e.g., soldered thereto). It is recognized, however,that the DBC adds significant cost to the packaging structure both froma materials standpoint and from a processing standpoint—as additionalprocessing steps and temperature excursions are required when includinga DBC in the packaging structure, such as soldering and flux cleaningprocesses required for joining the DBC to the packaging structure. It isalso recognized that the wirebonds and leads add significant parasiticinductance that reduces the efficiency of the package. Wirebonds alsoadd significant height to the package. It is still further recognizedthat—while the leads on the packaging structure allow higher thermalcycling reliability and are not subject to stringent MoistureSensitivity Level (MSL) Requirements—the leads or terminals in a powermodule can be quite large and affect the module foot-print and thicknesson the PCB and also negatively impact the electrical performance due tohigh inductance.

Therefore, it would be desirable to provide a semiconductor devicepackage structure that eliminates the need for a multi-layer DBC or PCBsubstrate and wirebond connections, so as to provide a very thin packagestructure with ultra low inductance. It would further be desirable forsuch a package structure to have a high device density and a smallfoot-print, so as to enable system miniaturization to improve electricaland reliability performance of the package.

BRIEF DESCRIPTION OF THE INVENTION

In accordance with one aspect of the invention, a package structureincludes a first dielectric layer, at least one semiconductor deviceattached to the first dielectric layer, and an embedding materialapplied to the first dielectric layer so as to embed the at least onesemiconductor device therein, the embedding material comprising one ormore additional dielectric layers. The package structure also includes aplurality of vias formed in the first dielectric layer formed to the atleast one semiconductor device, metal interconnects formed in theplurality of vias and on one or more outward facing surface of thepackage structure to form electrical interconnections to the at leastone semiconductor device, and input/output (I/O) connections located onone end of the package structure on one or more outward facing surfacesthereof to provide a second level connection to an external circuit. Thepackage structure is configured to interfit with a connector formed onthe external circuit to mount the package perpendicular to the externalcircuit, with the I/O connections on the one end of the packagestructure being electrically connected to the connector to form thesecond level connection to the external circuit.

In accordance with another aspect of the invention, a method ofmanufacturing a semiconductor device package structure includesattaching at least one semiconductor device to a first dielectric layerby way of an adhesive, applying an embedding material on the firstdielectric layer so as to be positioned about the at least onesemiconductor device, and performing a lamination process to cause theembedding material to fill any air gaps present around the at least onesemiconductor device and so as to embed the at least one semiconductordevice therein, wherein the first dielectric layer does not melt or flowduring the lamination process. The method also includes forming aplurality of vias to the at least one semiconductor device, formingmetallic interconnects in the plurality of vias and over at least aportion of one or more outer surfaces of the package structure to formelectrical interconnections to the at least one semiconductor device,and forming input/output (I/O) connections on one or more of the outwardfacing surfaces of the package structure, at only one end of the packagestructure, the I/O connections comprising electrical leads that providea second level connection to an external circuit.

In accordance with yet another aspect of the invention, a packagestructure includes a first dielectric layer having an adhesive appliedon at least a portion thereof, one or more semiconductor devicesattached to the first dielectric layer by way of the adhesive, anembedding material positioned on the first dielectric layer about theone or more semiconductor devices so as to embed the one or moresemiconductor devices therein, a plurality of vias formed to the atleast one semiconductor device, metal interconnects formed in theplurality of vias to form all electrical and thermal interconnections tothe one or more semiconductor devices and in the package structure andinput/output (I/O) connections formed on at least one outer surface ofthe package structure to provide a second level connection to anexternal circuit, wherein the I/O connections are configured to interfitwith a socket or recess formed in the external circuit, such that thepackage structure is partially embedded in the external circuit when theI/O connections of the package structure are interfit in socket orrecess.

These and other advantages and features will be more readily understoodfrom the following detailed description of preferred embodiments of theinvention that is provided in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings illustrate embodiments presently contemplated for carryingout the invention.

In the drawings:

FIG. 1 is a schematic cross-sectional side view of a power overlay (POL)package structure, according to an embodiment of the invention.

FIG. 2 is a schematic cross-sectional side view of a POL packagestructure, according to an embodiment of the invention.

FIG. 3 is a schematic cross-sectional side view of a POL packagestructure, according to an embodiment of the invention.

FIGS. 4A and 4B are front and back views of input/output (I/O)connections formed on one end of the POL package structures of FIGS. 1and 2.

FIGS. 5A and 5B are front and side views of the POL package structuresof FIGS. 1 and 2 inserted/embedded into a connector of a printed circuitboard (PCB), according to an embodiment of the invention.

FIG. 6 is a side view of a POL package structure inserted/embedded intoa connector of a printed circuit board (PCB), according to an embodimentof the invention.

FIG. 7 is a side view of the POL package structures of FIGS. 1 and 2inserted/embedded into a connector of a printed circuit board, with heatsinks affixed to the package structure and PCB, according to anembodiment of the invention.

FIG. 8 is a schematic cross-sectional side view of a POL packagestructure mounted on/embedded in a PCB, according to an embodiment ofthe invention.

FIG. 9 is a schematic cross-sectional side view of a POL packagestructure mounted on/embedded in a PCB, according to an embodiment ofthe invention.

DETAILED DESCRIPTION

Embodiments of the present invention provide for an embedded powermodule package structure having power overlay (POL) interconnects thatform all electrical and thermal interconnections to the semiconductordevices in the power module, as well as a method of forming such apackage structure. The package structure is constructed to have an“ultra-thin” construction in two axes, and may be partially embedded inan external circuit (e.g., PCB) to which the package structure ismounted.

Referring to FIG. 1, a POL packaging and interconnect structure 10 isshown according to an embodiment of the invention. The package structure10 includes one or more semiconductor devices 12, 13 that can be in theform of either what can generally be described as a “power device” or a“non-power device”, and thus can be in the form of a die, diode, MOSFET,transistor, application specific integrated circuit (ASIC), orprocessor, for example. While three power semiconductor devices 12 and asingle non-power semiconductor device 13 (i.e., gate driver) are shownin FIG. 1, it is recognized that a lesser or greater number ofsemiconductor devices or electronic components could be included in thePOL structure 10. The semiconductor devices 12, 13 are packaged withinpackage structure 10 such that direct metallic interconnects form allelectrical and/or thermal interconnections to the device.

As shown in FIG. 1, according to an exemplary embodiment, the packagestructure 10 includes a dielectric layer on each of opposing sides ofthe package structure 10 (with the semiconductor devices 12, 13positioned therebetween), with the layers being generally referred to asa first dielectric layer 14 and a second dielectric layer 16. Whilepackage structure 10 includes both first dielectric layer 14 and asecond dielectric layer 16, it is recognized that embodiments of theinvention may only include a first dielectric layer 14. In FIG. 1, thedielectric layers 14, 16 are provided in the form of a lamination orfilm and are formed of a material that is chosen to provide mechanicaland temperature stability to vias during use and frame processing, aswell as provide suitable dielectric properties and voltage breakdownstrength and processability for via formation and POL processing—andthus the dielectric layers 14, 16 can be referred to as a “POLdielectric.” Additionally, the material from which dielectric layers 14,16 is formed is chosen to remain stable during a lamination processperformed on the package structure 10. That is, dielectric layers 14, 16are formed of a suitable material such that they are configured to notflow during a lamination process performed on the package structure 10.Accordingly, the dielectric layers 14, 16 may be formed of one aplurality of dielectric materials, such as Kapton®, Ultem®,polytetrafluoroethylene (PTFE), Upilex®, polysulfone materials (e.g.,Udel®, Radel®), or another polymer film, such as a liquid crystalpolymer (LCP) or a polyimide material, according to embodiments of theinvention. For purposes of clarity and distinguishing of the dielectriclayers 14, 16 from other dielectric materials in the package structure10, the dielectric layers 14, 16 are hereafter referred to as polyimidelayers 14, 16, although this term is not meant to limit formation of thelayers 14, 16 from a specific dielectric material.

As shown in FIG. 1, polyimide layers 14, 16 are provided on both sidesof the package structure 10, i.e., on front and back surfaces 18, 20 ofthe package structure, so as to provide the ability to form vias andpatterned metal interconnects on both surfaces, as will be explainedfurther below. The semiconductor devices 12, 13 are positioned betweenthe polyimide layers 14, 16, with the devices 12, 13 being attached tothe polyimide layers 14, 16 by way of an adhesive 22. According toembodiments of the invention, an embedding material 24 (i.e.,encapsulant) is included in package structure 10 that is providedbetween the polyimide layers 14, 16 that serves to fill-up empty gapswithin the package structure 10 that might be present around thesemiconductor devices 12, 13 and between the polyimide layers 14, 16and, according to one embodiment, may ‘glue’ the polyimide layer 14 tothe devices 12, 13, and thus may be formed of one or more materials.

According to one embodiment of the invention, and as shown in FIG. 1,the embedding material 24 is comprised of one or more dielectric layers26 that are provided in a ‘film’ or ‘panel’ or ‘sheet’ form, such that,if required, multiple dielectric sheets 26 can be stacked on one anotherto a required height/thickness required to fill in an area about thesemiconductor devices 12, 13 and between the polyimide layers 14, 16.The dielectric sheets 26 are formed from an electrically insulatingmaterial, such as a prepreg material, printed circuit board corematerial, polymeric resin, or other suitable adhesive, for example.According to one embodiment, the electrically insulating dielectricsheets 26 may be provided in a form that is either uncured or partiallycured (i.e., B-stage), such that they can be easily stacked in theirpre-cure film form. According to another embodiment, the electricallyinsulating dielectric sheets 26 may be provided as both cured anduncured sheets, such as sheets of a cured core material and sheets of aflowable prepreg material or a mixture of sheets of polyimide and aflowable adhesive (e.g., layer 22). Other insulating materials may alsobe used such as ceramics or glass. According to one embodiment of theinvention, the dielectric sheet(s) 26 include openings/cut-outs 28formed therein to receive the semiconductor devices 12, 13 therein andaccommodate positioning of the sheet(s) 26 thereabout. Alternatively, itis recognized that segments of dielectric sheets 26 could be placedabout the semiconductor devices 12, 13.

While embedding material 24 is described above as being comprised of oneor more dielectric layers 26 that are provided in a ‘film’ or ‘panel’ or‘sheet’ form, it is recognized that embedding material 24 could includeother materials. For example, the dielectric stack that is the embeddingmaterial 24 can be comprised of a layer of metal or a dielectric filmwith thick copper, for example, that does not melt and flow whensubjected to a lamination process. In such embodiments, these layerswould be electrically isolated as needed from the devices 12, 13, butbeneficially could function as a heat-spreading embedded structure thatcan be connected with vias to spread heat and conduct to the ambient.These embedded layers with metallization can also be patterned andinterconnected to provide additional routing layers for added circuitdensity.

In order to fill-up empty gaps within the package structure 10, thedielectric sheet(s) 26 are subjected to a lamination/curing process(typically in vacuum environment, at elevated temperature and undermechanical pressure) that causes all or some of the dielectric sheet(s)26 to “melt” and flow. The dielectric sheet(s) 26 thus lose their filmform and flow to fill up any empty air gaps around the semiconductordevices 12, 13 and between the polyimide layers 14, 16, such that adielectric encapsulant 24 is provided that protects the semiconductordevices 12, 13 from the ambient environment in general and providesmechanical integrity and electrical isolation.

Referring now to FIG. 2, an alternate embodiment of package structure 10is shown in which the embedding material 24 is formed only of adhesive22. That is, in cases where the semiconductor devices 12, 13 are verythin, no dielectric layers 26 may be required to encapsulate thesemiconductor devices. Instead, the adhesive 22 is coated on the surfaceof the polyimide layer 14, beyond the area in which the semiconductordevices 12, 13 are attached, and during lamination, this adhesive 22 issufficient to fill the gaps around the semiconductor devices 12, 13between the polyimide layers 14, 16. While the polyimide layers 14, 16are shown in FIG. 2 as being parallel to one another, it is recognizedthat such an arrangement of the polyimide layers 14, 16 is not required,as the gap between the two polyimide layers 14, 16 may be smaller inareas where the die are not present so as to result in an arrangementwhere the polyimide layers 14, 16 are not parallel.

In each of the embodiments of package structure 10 shown in FIGS. 1 and2, a plurality of vias 30 is formed through polyimide layer 14 down to afront surface 32 of the semiconductor devices 12, 13. For powersemiconductor devices 12, vias 30 may all be formed to front surface 32of the semiconductor devices 12 (e.g., as for GaN power devices) or mayinstead be formed to both the front surface and back surface 34 of thesemiconductor devices 12, to meet electrical and thermal requirements(e.g., to make electrical connection that is needed and remove heat fromthe power semiconductor device). Metal interconnects 38 are subsequentlyformed in the package structure 10 to provide electrical and thermalconnections/pathways therein, with the interconnects 38 being formed inthe vias 30 and out onto the outward facing front and back surfaces 18,20 of the polyimide layers 14, 16, respectively, such that both frontand back surfaces 18, 20 of the package structure 10 includeinterconnects formed thereon. According to embodiments of the invention,the metal interconnects 38 comprise “POL interconnects” that are formedas robust electroplated copper interconnects that form direct electricalconnections in the devices 12, 13. Depending on the metallization on thedevice, in some embodiments, a sputtered adhesion layer (titanium,chromium, etc.) is provided along with a sputtered copper seed layer onwhich copper can be plated. As shown in FIGS. 1 and 2, the metalinterconnects 38 are patterned and etched to a desired shape, such as toprovide for electrical and thermal connections to package structure 10.According to one embodiment, metal interconnects 38 are patterned andetched to provide a large area thermal and electrical connection on thefront and/or back side of package structure 10 (i.e., copper pad) thatenables attachment of the package structure to a heatsink, for example,as will be explained in greater detail further below.

While the package structures 10 of FIGS. 1 and 2 are shown as onlyincluding dielectric layers 14, 16 having metal interconnects 38 formedtherein, it is recognized that a further build-up of the package couldbe performed. That is, as shown in FIG. 3, one or more additional metalcircuit layers 39 (i.e., dielectric layer and patterned metalinterconnect) could be applied to each of the front and back surfaces18, 20 of the package structure to increase routing in the packagestructure 10.

According to another embodiment, rather than adding additional metalcircuit layers to the package structure 10 (as in FIG. 3), routing couldbe increased in the package structure by adding a metal layer (notshown) on the inward side of dielectric layers 14, 16 (i.e., on the sideof the devices 12, 13). In such an embodiment, metal layers would thusbe present on both sides of each dielectric layer 14, 16.

Referring now to FIGS. 1-3, according to embodiments of the invention,electrical input/output connections (I/Os) 40 are provided on packagingstructure 10 that serve as “electrical leads” that electrically connectthe package structure 10 to an external circuit, such as a printedcircuit board (PCB)—i.e., the I/O connections 40 are utilized to form asecond-level interconnection to an external circuit. The I/O connections40 may be formed as copper pads or traces of plated copper, for example,that are formed on the front and/or back surfaces 18, 20 of the packagestructure. The I/O connections establish full electrical functionalityat the system-level, such that additional/separate leads, terminals or alead-frame is not needed in the POL package structure 10, resulting inan ultra-thin, miniaturized electrical package with greatly improvedelectrical and mechanical performance.

According to an exemplary embodiment of the invention, the I/Oconnections 40 that provide the second-level interconnection to the PCBare all located on one end 42 of the package structure on one or both ofthe front and back surfaces 18, 20. Detailed views of the end 42 atwhich the I/O connections 40 are formed are shown in FIGS. 4A and 4B,which illustrate the front and back surfaces 18, 20 of the packagestructure 10 at the end 42. As shown in FIGS. 4A and 4B, the copper padsand/or traces of plated copper forming leads 44 (on dielectric layer 14,16) of the I/O connections 40 are formed at the end 42 of the packagestructure 10. According to one embodiment, and as best seen in FIGS. 1and 2, a soldermask 46 may be applied over a remainder of the frontand/or back surfaces 18, 20—i.e., over the patterned POL interconnects38—to provide a protective coating for the copper thereof, while leavingthe I/O connections 40 on the end 42 uncovered. Additionally, it isrecognized that a solder finish or other metal finish (not shown) may beapplied on the exposed areas of patterned POL interconnects 38 (leftexposed by the solder mask) or the entire surface of the patterned POLinterconnects 38.

By providing the I/O connections 40 of the package structure 10 all onend 42, the package structure 10 is constructed to be connected to a PCBon-edge. Such an arrangement of the package structure 10 with a PCB 48is shown via front and side views in FIGS. 5A and 5B, with the end 42 ofthe package structure 10 being inserted into a connector or socket 50 onthe PCB 48 such that the I/O connections 40 form a direct electricalconnection with the connector 50. The mounting of package structure 10on-edge in an upright orientation (i.e., perpendicular) relative to thePCB 48 minimizes the footprint of the package structure 10 and thussaves board area, although it does serve to increase the height of thePCB assembly. However, according to one embodiment of the invention, theheight of the package structure 10 can be reduced by bending the packagestructure after insertion into socket 50, as shown in FIG. 6. Uponbending, a portion/majority of the package structure 10 is parallel tothe PCB 48, with one embodiment being constructed such that the portionof the package structure including the dies/semiconductor devices isparallel to the PCB.

Referring now to FIG. 7, according to one embodiment of the invention,one or more heat sinks 52 are coupled to the package structure 10 on thefront and/or back surfaces 18, 20 to assist in heat removal andfacilitate thermal management of the package structure. While FIG. 7shows two heat sinks 52 being affixed to package structure 10, it isrecognized that only a single heat sink 52 may be attached to thepackage structure, such as to back side 20 thereof. The heat sinks 52may be coupled to the package structure 10 such as by adding thermalinterface material(s) (TIM) 54 to the backside 20 (and/or front side 18)of the structure. That is, a layer of TIM 54 having a thermalconductivity is applied onto the POL structure 10 and over the POLinterconnects 38 (and soldermask 46) to provide bonding and the thermaltransfer of energy to the heat sinks 52. Examples of suitable TIMsinclude, without limitation, adhesives, greases, gels, pads, films,liquid metals, compressible metals, and phase change materials. Liquidmetal TIMs, for example, are typically indium-gallium alloys that are inliquid state over temperatures typically encountered in powerelectronics applications. Compressible metals are sufficiently soft tomake intimate contact between a heatsink and POL mating surfaces and mayinclude, for example, indium.

In addition to the heat sinks 52 enhancing heat removal from the packagestructure 10, the heat sinks 52 also provide mechanical support to thepackage structure in its on-edge mounting to the PCB 48. That is, inaddition to being affixed to package structure 10 (via TIM 54), the heatsinks 52 are also coupled to the PCB 48 such that they provide bracingfor the package structure 10. Depending on whether one or two heat sinks52 are attached to the package structure 10, the heat sinks 52 may thusprovide additional structural support to the package structure 10 oneither one or both sides thereof to help maintain the package structure10 in its upright orientation relative to the PCB 48.

Referring now to FIGS. 8 and 9, package structures 60, 62 are shownaccording to additional embodiments of the invention, where the packagestructures are constructed to be partially embedded in an externalcircuit (e.g., PCB) to which the package structure is mounted, with thepackage structures having an “ultra-thin” construction in two axes. Thepackage structures 60, 62 shown in FIGS. 8 and 9 have a similarconstruction to the package structures 10 illustrated in FIGS. 1 and 2in regards to the embedding of semiconductor devices in an embeddingmaterial between dielectric layers and the use of POL interconnects, andthus components in the package structures 60, 62 of FIGS. 8 and 9identical to corresponding components in the package structure 10 ofFIGS. 1 and 2 are similarly numbered.

As shown in FIGS. 8 and 9, each of the package structures 60, 62 isshown as including semiconductor devices 12, 13 positioned between afirst dielectric layer 14 and a second dielectric layer 16 (i.e.,polyimide layers), with the devices 12, 13 being attached to thepolyimide layers 14, 16 by way of an adhesive 22 and being encapsulatedby an embedding material that is formed from a one or more dielectriclayers 26. The dielectric layer(s) are provided in a ‘film’ or ‘panel’or ‘sheet’ form that can be stacked on one another to a requiredheight/thickness required to fill in an area about the semiconductordevices 12, 13 and between the polyimide layers 14, 16, with thedielectric sheets 26 being caused to melt and flow when subjected to alamination/curing process, such that the dielectric sheet(s) 26 thuslose their film form and flow to fill up any empty air gaps around thesemiconductor devices 12, 13 and between the polyimide layers 14, 16.

In the package structures 60, 62 a plurality of vias 30 is formedthrough polyimide layer 14 down to a front surface 32 of thesemiconductor devices 12, 13. For power semiconductor devices 12, vias30 are also formed to back surface 34 of the semiconductor devices 12 tomeet electrical and thermal requirements. Metal interconnects 38 aresubsequently formed in the package structure 10 to provide electricaland thermal connections/pathways therein, with the interconnects 38being formed in the vias 30 and out onto the outward facing front andback surfaces 18, 20 of the polyimide layers 14, 16, respectively, suchthat both front and back surfaces 18, 20 of the package structure 10include interconnects formed thereon. According to embodiments of theinvention, the metal interconnects 38 comprise “POL interconnects” thatare formed as robust electroplated copper interconnects that form directelectrical connections in the devices 12, 13. The metal interconnects 38are patterned and etched to a desired shape, such as to provide forelectrical and thermal connections to package structure 10.

Referring to FIG. 8, electrical input/output connections (I/Os) 64 areprovided on packaging structure 10 at each of generally opposing ends 66of the structure that serve as “electrical leads” that electricallyconnect the package structure 10 to an external circuit 48, such as aprinted circuit board (PCB). According to an embodiment, and as shown inFIG. 8, I/O connections 64 are formed on the front surface 18 of thepackage structure 10. Thru-vias 68 are thus be formed through polyimidelayers 14, 16 and dielectric sheet(s) 26 that are metalized (i.e., metalinterconnects 38 are formed in/through thru-vias 68) to redistributeelectrical connections from the back surface 20 to the front surface 18.While I/O connections 64 are shown as being formed on only the frontsurface 18 of the package structure 10, it is recognized that the I/Oconnections 64 could instead be formed on both surfaces of thepackage—i.e., on front and back surfaces 18, 20—with the thru-vias 68not being present in such an embodiment.

As shown in FIG. 8, the I/O connections 64 formed on the front surface18 of the package structure 10 includes leads 70—with the leads 70 beingformed as copper pads or traces of plated copper, for example, that areoriented generally parallel to the surface 18 of the package structureand that are utilized to form a second-level interconnection to the PCB48. A soldermask 46 may be applied over a remainder of the front surface18—i.e., over the patterned POL interconnects 38—to provide a protectivecoating for the copper thereof, while leaving the leads 70 of I/Oconnections 64 on the front surface 18 uncovered. Additionally, it isrecognized that a solder finish or other metal finish (not shown) may beapplied on the exposed areas of patterned POL interconnects 38 (leftexposed by the solder mask) or the entire surface of the patterned POLinterconnects 38. As shown in FIG. 8, the package structure 60 isarranged in a “flat” or parallel orientation relative to the PCB 48 andis partially embedded into PCB 48 via positioning of the packagestructure into a recess 52 of the PCB 48, with solder 72 being appliedat the location of the leads 70, so as to establish full electricalfunctionality at the system-level. In this manner, additional/separateleads, terminals or a lead-frame is not needed in the POL packagestructure 10, resulting in an ultra-thin, miniaturized electricalpackage with greatly improved electrical and mechanical performance. Asthe package structure 60 is partially embedded into PCB 48, a height ofthe PCB assembly is reduced as compared to an assembly where the packagestructure is mounted to a generally planar PCB without a recess forreceiving a package structure.

Referring now to FIG. 9, the package structure 62 includes I/Oconnections 64 formed on the front surface 18 of the package structure10 that includes leads 74 that extend out perpendicularly from frontsurface 18—so as to provide a connectorized construction for the packagestructure 62. That is, rather than the leads 74 of the I/O connections64 on the front surface 18 being structured as flat copper pads/tracesas in the embodiment of FIG. 8, the leads 74 of I/O connections 64 areformed as copper wires or traces (alone or include polyimide material,i.e., polyimide 14) that are bent so as to extend perpendicularlyoutward from front surface 18 of the package structure 62. As shown inFIG. 9, the bent leads 74 of the I/O connections 64 are configured to beinserted/embedded within slots or a socket 76 formed in/on the PCB 48.The leads 74 could then be secured in the slots/socket 76 via sintering,soldering or a mechanical connection (e.g., press-fit), so as toestablish full electrical functionality at the system (i.e., asecond-level interconnection to the PCB).

Beneficially, embodiments of the invention thus provide a packagestructure having an “ultra-thin” construction in two axes, with theconstruction enabling the package structure to be partially embedded inan external circuit (e.g., PCB) to which the package structure ismounted. The use of POL interconnects and I/O connections in the packagestructure 10 eliminate the need for wire bonds and/or an additionalmulti-layer substrate (like a DBC substrate, etc.) that would typicallybe used for electrical and thermal functionality, thereby providing apackage with ultra low inductance by providing a small inductance loopand flux cancellation and the elimination of wirebonds and/or largerleads/terminals that can increase inductance. Such elimination of thewire bonds and multi-layer substrate in packaging a power device in thepackage structure 10 also enables a package structure 10 having a verysmall form-factor with high device density and a small foot-print, so asto enable system miniaturization to improve electrical and reliabilityperformance of the package. The I/O connections of the package structureallow the package structure to be partially embedded in an externalcircuit, with embodiments of the invention providing for mounting of thepackage structure in a connector or recess of the PCB eitheron-edge/vertical relative to the PCB (so as to reduce a board footprintof the package structure) or flat within a recess of the PCB (to reducean overall height of the PCB assembly).

Therefore, according to one embodiment of the invention, a packagestructure includes a first dielectric layer, at least one semiconductordevice attached to the first dielectric layer, and an embedding materialapplied to the first dielectric layer so as to embed the at least onesemiconductor device therein, the embedding material comprising one ormore additional dielectric layers. The package structure also includes aplurality of vias formed in the first dielectric layer formed to the atleast one semiconductor device, metal interconnects formed in theplurality of vias and on one or more outward facing surface of thepackage structure to form electrical interconnections to the at leastone semiconductor device, and input/output (I/O) connections located onone end of the package structure on one or more outward facing surfacesthereof to provide a second level connection to an external circuit. Thepackage structure is configured to interfit with a connector formed onthe external circuit to mount the package perpendicular to the externalcircuit, with the I/O connections on the one end of the packagestructure being electrically connected to the connector to form thesecond level connection to the external circuit.

According to another embodiment of the invention, a method ofmanufacturing a semiconductor device package structure includesattaching at least one semiconductor device to a first dielectric layerby way of an adhesive, applying an embedding material on the firstdielectric layer so as to be positioned about the at least onesemiconductor device, and performing a lamination process to cause theembedding material to fill any air gaps present around the at least onesemiconductor device and so as to embed the at least one semiconductordevice therein, wherein the first dielectric layer does not melt or flowduring the lamination process. The method also includes forming aplurality of vias to the at least one semiconductor device, formingmetallic interconnects in the plurality of vias and over at least aportion of one or more outer surfaces of the package structure to formelectrical interconnections to the at least one semiconductor device,and forming input/output (I/O) connections on one or more of the outwardfacing surfaces of the package structure, at only one end of the packagestructure, the I/O connections comprising electrical leads that providea second level connection to an external circuit.

According to yet another embodiment of the invention, a packagestructure includes a first dielectric layer having an adhesive appliedon at least a portion thereof, one or more semiconductor devicesattached to the first dielectric layer by way of the adhesive, anembedding material positioned on the first dielectric layer about theone or more semiconductor devices so as to embed the one or moresemiconductor devices therein, a plurality of vias formed to the atleast one semiconductor device, metal interconnects formed in theplurality of vias to form all electrical and thermal interconnections tothe one or more semiconductor devices and in the package structure andinput/output (I/O) connections formed on at least one outer surface ofthe package structure to provide a second level connection to anexternal circuit, wherein the I/O connections are configured to interfitwith a socket or recess formed in the external circuit, such that thepackage structure is partially embedded in the external circuit when theI/O connections of the package structure are interfit in socket orrecess.

While the invention has been described in detail in connection with onlya limited number of embodiments, it should be readily understood thatthe invention is not limited to such disclosed embodiments. Rather, theinvention can be modified to incorporate any number of variations,alterations, substitutions or equivalent arrangements not heretoforedescribed, but which are commensurate with the spirit and scope of theinvention. Additionally, while various embodiments of the invention havebeen described, it is to be understood that aspects of the invention mayinclude only some of the described embodiments. Accordingly, theinvention is not to be seen as limited by the foregoing description, butis only limited by the scope of the appended claims.

What is claimed is:
 1. A circuit board and package structure arrangementcomprising: a circuit board comprising a recess formed therein; and apackage structure configured to interfit with the recess formed in thecircuit board, the package structure comprising: a first dielectriclayer having a first adhesive applied on at least a portion thereof; asecond dielectric layer spaced apart from the first dielectric layer andhaving a second adhesive applied on at least a portion thereof; one ormore semiconductor devices attached to the first dielectric layer and tothe second dielectric layer by way of the first adhesive and secondadhesive, respectively, with a front surface of each of the one or moresemiconductor devices attached to the first dielectric layer and a backsurface of each of the one or more semiconductor devices attached to thesecond dielectric layer; an embedding material positioned between thefirst and second dielectric layers and about the one or moresemiconductor devices so as to embed the one or more semiconductordevices therein; a plurality of vias formed through the first dielectriclayer and the second dielectric layer to the front and back surfaces ofthe one or more semiconductor devices; metal interconnects formed in theplurality of vias to form electrical and thermal interconnections to thefront and back surfaces of the one or more semiconductor devices; andinput/output (I/O) connections formed on at least one outer surface ofthe package structure to provide a second level connection to thecircuit board; wherein the package structure interfits with the recessformed in the circuit board, such that the package structure ispartially embedded in the circuit board, with the first dielectric layerand at least a portion of the embedding material being positioned belowa top surface of the circuit board when the package structure isinterfit with the recess.
 2. The circuit board and package structurearrangement of claim 1 wherein the I/O connections are formed at each ofopposing edges of the package structure and configured to form thesecond level connection to the external circuit, the I/O connectionscomprising electrical leads that interfit with the recess formed in theexternal circuit such that the package structure is arranged in a flator parallel orientation relative to the external circuit.
 3. The circuitboard and package structure arrangement of claim 1 wherein the pluralityof vias extend through the first and second adhesives.
 4. The circuitboard and package structure arrangement of claim 1 wherein the at leastone semiconductor device comprises a power semiconductor device; andwherein the plurality of vias comprises: first vias formed through thefirst dielectric layer and the first adhesive to the front surface ofthe power semiconductor device; and second vias formed through thesecond dielectric layer and the second adhesive to the back surface ofthe power semiconductor device; wherein the first and second viasfunction as thermal and electrical vias in the package structure; andwherein metal interconnects are formed in each of the first and secondvias to the front and back surfaces of the power semiconductor device.5. The circuit board and package structure arrangement of claim 4further comprising a metal layer positioned on an inward facing surfaceof the first dielectric layer or the second dielectric layer to increaserouting in the package structure.
 6. The circuit board and packagestructure arrangement of claim 1 wherein the embedding materialcomprises a plurality of dielectric sheets formed of a materialconfigured to melt and flow when subjected to a lamination process, soas to fill-in any air gaps present around the at least one semiconductordevice.
 7. The circuit board and package structure arrangement of claim6 wherein the embedding material further comprises a metal layer or adielectric sheet with copper thermally connected to the plurality ofvias to spread and conduct heat to an ambient environment, with themetal layer or dielectric sheet with copper constructed to not melt andflow when subjected to the lamination process.
 8. A circuit board andpackage structure arrangement comprising: a circuit board comprising arecess formed therein; and a package structure configured to interfitwith the recess formed in the circuit board, the package structurecomprising: a first dielectric layer having an adhesive applied on atleast a portion thereof; one or more semiconductor devices attached tothe first dielectric layer by way of the adhesive; an embedding materialpositioned on the first dielectric layer about the one or moresemiconductor devices so as to embed the one or more semiconductordevices therein; a plurality of vias formed to the at least onesemiconductor device; metal interconnects formed in the plurality ofvias to form electrical and thermal interconnections to the one or moresemiconductor devices and in the package structure; and input/output(I/O) connections formed on at least one outer surface of the packagestructure to provide a second level connection to the circuit board;wherein the package structure interfits with the recess formed in thecircuit board such that the package structure is partially embedded inthe circuit board, with the first dielectric layer and at least aportion of the embedding material being positioned below a top surfaceof the circuit board when the package structure is interfit with therecess.
 9. The circuit board and package structure arrangement of claim8 wherein the circuit board comprises a solder applied at a locationwithin the recess adjacent to the I/O connections when the packagestructure is interfit with the recess, with the solder providing anelectrical connection between the circuit board and the packagestructure.
 10. The circuit board and package structure arrangement ofclaim 9 wherein the I/O connections comprise electrical leads formed asflat pads or traces parallel to an orientation of the package structure.11. The circuit board and package structure arrangement of claim 8further comprising a second dielectric layer positioned on an outersurface of the package structure opposite the first dielectric layer,with the one or more semiconductor devices positioned between the firstdielectric layer and the second dielectric layer.
 12. The circuit boardand package structure arrangement of claim 8 wherein the packagestructure is connected to the circuit board without the use of wirebonds or a multilayer insulating substrate.
 13. The circuit board andpackage structure arrangement of claim 8 wherein the recess formed inthe circuit board is sized to receive an entirety of a footprint of thepackage structure therein.
 14. A circuit board and package structurearrangement comprising: a circuit board comprising a recess formedtherein; and a package structure configured to interfit with the recessformed in the circuit board, the package structure comprising: a firstdielectric layer having an adhesive applied on at least a portionthereof; one or more semiconductor devices each having a front surfaceand a back surface, with the front surface of each of the one or moresemiconductor devices attached to the first dielectric layer by way ofthe adhesive; an embedding material positioned on the first dielectriclayer about the one or more semiconductor devices so as to embed the oneor more semiconductor devices therein; a second dielectric layerpositioned opposite the first dielectric layer and attached to the backsurface of each of the one or more semiconductor devices via anotheradhesive, with the one or more semiconductor devices positioned betweenthe first dielectric layer and the second dielectric layer and theembedding material being fully contained between the first dielectriclayer and the second dielectric layer; a plurality of vias formedthrough the first dielectric layer and the second dielectric layer tothe front surface and the back surface of each of the one or moresemiconductor devices; and metal interconnects formed in the pluralityof vias to form electrical and thermal interconnections to the front andback surfaces of each of the one or more semiconductor devices and inthe package structure; and input/output (I/O) connections formed on anouter surface of the package structure to provide a second levelconnection to the circuit board; wherein the package structure interfitswith the recess formed in the circuit board, such that the packagestructure is partially embedded in the circuit board, with the firstdielectric layer and at least a portion of the embedding material beingpositioned below a top surface of the circuit board when the packagestructure is interfit with the recess.
 15. The circuit board and packagestructure arrangement of claim 14 wherein the outer surface of thepackage structure having the I/O connections formed thereon is free of amultilayer insulating substrate that provides electrical and thermalconnectively between the package structure and the external circuit.